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 Posted Thursday, March 6, 2008 7:04 AM
 SSCommitted Group: General Forum Members Last Login: Today @ 2:56 PM Points: 1,522, Visits: 750
 Only the second query is getting the right answer. #1 and #3 are getting +1 to the my current age.
Post #465123
 Posted Thursday, March 6, 2008 7:09 AM
 Ten Centuries Group: General Forum Members Last Login: Thursday, August 18, 2016 5:39 AM Points: 1,160, Visits: 3,359
 The third solution is clearly incorrect - given a datetime value of 01/26/1978. i.e.`declare @DateOfBirth datetimeset @DateOfBirth = '1978-01-26 00:00:00.000'select @DateOfBirthselect DATEDIFF(yy, @DateOfBirth, GETDATE()) select FLOOR(CONVERT(decimal(9, 2), DATEDIFF(d, @DateOfBirth, GETDATE())) / 365.0) select DATEDIFF(yy, @DateOfBirth, GETDATE()) - CASE WHEN DATEPART(m, @DateOfBirth) >= DATEPART(m, GETDATE()) AND DATEPART(d, @DateOfBirth) >= DATEPART(d, GETDATE()) THEN 0 ELSE 1 END `Returns:30 - Correct30 - Correct29 - Incorrect TommyFollow @sqlscribe
Post #465125
 Posted Thursday, March 6, 2008 7:09 AM
 SSCommitted Group: General Forum Members Last Login: Today @ 11:11 AM Points: 1,643, Visits: 6,987
 I intuitively choose 2 because 1 and 3 are definitely wrong. 1 doesn't take care of month and day of birth at all and 3 does it in the wrong way. But the are all wrong. It can be easily verified with the script below. Play around with some values at the beginning and end of the month in both dates. I added a fourth solution which I think is correct.`declare @DateOfBirth datetimedeclare @Today datetimeselect @DateOfBirth = '2004/03/01'select @Today = '2008/02/29'select DATEDIFF(yy, @DateOfBirth, @today) select FLOOR(CONVERT(decimal(9, 2), DATEDIFF(d, @DateOfBirth, @Today)) / 365.0) select DATEDIFF(yy, @DateOfBirth, @today) - CASE WHEN DATEPART(m, @DateOfBirth) >= DATEPART(m, @Today) AND DATEPART(d, @DateOfBirth) >= DATEPART(d, @Today) THEN 0 ELSE 1 END select DATEDIFF(yy, @DateOfBirth, @today) - CASE WHEN DATEPART(m, @Today) > DATEPART(m, @DateOfBirth) OR (DATEPART(m, @Today) = DATEPART(m, @DateOfBirth) AND DATEPART(d, @Today) >= DATEPART(d, @DateOfBirth)) THEN 0 ELSE 1 END `
Post #464921
 Posted Thursday, March 6, 2008 7:26 AM
 Ten Centuries Group: General Forum Members Last Login: Monday, February 22, 2016 8:32 AM Points: 1,274, Visits: 1,992
 Of course, I suppose the real point of the question was to draw attention to the fact that (1) was wrong and (2) was inaccurate. But it would have been helpful to have a correct solution in the mix. :) Derek
Post #465138
 Posted Thursday, March 6, 2008 7:32 AM
 SSCrazy Group: General Forum Members Last Login: Monday, April 6, 2009 1:29 PM Points: 2,057, Visits: 215
 I originally thought the 1 and 0 were switched but actually, the two comparisons should be >=
Post #465141
 Posted Thursday, March 6, 2008 7:32 AM
 Hall of Fame Group: General Forum Members Last Login: 2 days ago @ 8:38 AM Points: 3,638, Visits: 981
 I also ran all three queries with my birthdate, and the first and third returned the wrong answer. However, the second one was correct.
Post #465142
 Posted Thursday, March 6, 2008 7:37 AM
 SSC Journeyman Group: General Forum Members Last Login: Thursday, May 23, 2013 6:20 AM Points: 96, Visits: 44
 That one works flawlessly.DECLARE @DateOfBirth VARCHAR(10)SET @DateOfBirth = '1960-03-07'print YEAR(GETDATE()) - YEAR(@DateOfBirth) - CASE WHEN MONTH(GETDATE())*31 + DAY(GETDATE()) >= MONTH(@DateOfBirth)*31 + DAY(@DateOfBirth) THEN 0 ELSE 1 END
Post #465147
 Posted Thursday, March 6, 2008 7:39 AM
 SSC Veteran Group: General Forum Members Last Login: Thursday, June 26, 2008 7:27 AM Points: 239, Visits: 165
 The formula is incorrect. If your birthday has occurred in the calendar year, the formula below returns 1 year less than it should. I know many people that would be happy if the formula was correct, but I am afraid they really are the age that DATEDIFF(yy, DateOfBirth, GETDATE()) gives.DATEDIFF(yy, DateOfBirth, GETDATE()) - CASE WHEN DATEPART(m, DateOfBirth) >= DATEPART(m, GETDATE()) AND DATEPART(d, DateOfBirth) >= DATEPART(d, GETDATE()) THEN 0 ELSE 1 END QPlease take a number. Now serving emergency 1,203,894
Post #465150
 Posted Thursday, March 6, 2008 7:44 AM
 SSCommitted Group: General Forum Members Last Login: Friday, September 2, 2016 8:40 AM Points: 1,571, Visits: 724
 Another point - the question specifies TINYINT, none of the queries return TINYINT. (1) is INT, (2) is DECIMAL, (3) is INT. Not only are the queries inaccurate, but none of them fit the criteria ...
Post #465157
 Posted Thursday, March 6, 2008 7:52 AM
 SSC Veteran Group: General Forum Members Last Login: Thursday, August 27, 2009 12:26 PM Points: 228, Visits: 61
 sorry the 3rd answer is not 100% correct as writtenDECLARE @DateOfBirth DATETIMESET @DateOfBirth='08/xx/1975' --commented out the day just becauseSELECT DATEDIFF(yy, @DateOfBirth, GETDATE()) AS [first], FLOOR(CONVERT(decimal(9, 2), DATEDIFF(d, @DateOfBirth, GETDATE())) / 365.0) AS [second],DATEDIFF(yy, @DateOfBirth, GETDATE()) - CASE WHEN DATEPART(m, @DateOfBirth) >= DATEPART(m, GETDATE()) AND DATEPART(d, @DateOfBirth) >= DATEPART(d, GETDATE()) THEN 0 ELSE 1 END AS [third]the result when it runsfirst second third33 32 33Don't age me before my time, only the second one was correct.
Post #465164

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